GB 31604.15-2016
Food contact materials--Polymer--Determination of 2, 4, 6-triamino-1, 3, 5-triazine (melamine) in food simulants--High performance liquid chromatography
National Standards of People's Republic of China
National food safety standards
Food Contact Materials and Products 2,4,6-Trisamino-
Determination of migration of 1,3,5-triazine (melamine)
Published on.2016-10-19
2017-04-19 Implementation
China
National Health and Family Planning Commission released
Foreword
This standard replaces GB/T 23296.15-2009 "food contact material polymer food simulant 2,4,6-triamino-
Determination of 1,3,5-triazine (melamine) by High Performance Liquid Chromatography.
Compared with GB/T 23296.15-2009, the main changes are as follows.
--- The standard name was changed to "National Food Safety Standard Food contact materials and products 2,4,6-triamino-1,3,5-triazine (trimerization
Cyanamide) Determination of Migration Amount".
National food safety standards
Food Contact Materials and Products 2,4,6-Trisamino-
Determination of migration of 1,3,5-triazine (melamine)
1 Scope
This standard specifies the method for determining the migration of melamine in food contact materials and products (melamine formaldehyde resin and its molded products).
This standard applies to food contact materials and products (melamine formaldehyde resin and its molded products) melamine migration of high-performance liquid-phase color
Spectral detection.
2 principle
Contact food contact materials and products (melamine-formaldehyde resin and its molded products) with food simulants under specific soaking conditions
The migration test was conducted and the test solution obtained after the soaking solution was detected by high performance liquid chromatography and converted into a specific migration amount of melamine. According to food
Product category, according to GB 31604.1 select the corresponding food simulants and migration test conditions (time, temperature). Food simulant is water,
When 4% (volume fraction) of acetic acid, 10%, 20%, 50% to 95% (volume fraction) of ethanol, the soaking solution was directly injected as a test solution; food simulants
In the case of vegetable oils, the test liquid obtained after the soaking liquid extraction treatment is directly injected, and the melamine contained in the test liquid is determined by high performance liquid chromatography.
Amount, in accordance with the provisions of GB 5009.156 to determine the migration test soaking liquid volume and sample contact area, according to the formula converted to melamine special
Determine the migration volume (migration amount).
3 Reagents and materials
Unless otherwise stated, the reagents used in this method are of analytical grade, and the water is a grade one water according to GB/T 6682. Test container and transfer
Appliances should avoid plastic materials.
3.1 Reagents
3.1.1 Water-based, acidic, alcoholic, oily food simulants. The reagents used are in accordance with the provisions of GB 31604.1.
3.1.2 Sodium hydroxide (NaOH).
3.1.3 Sodium dihydrogen phosphate dihydrate (NaH2PO4·2H2O).
3.1.4 Isopropanol [(CH3)2CHOH].
3.1.5 Methanol (CH3OH). Chromatographically pure.
3.1.6 Isooctane [(CH3)2CHCH2C(CH3)3].
3.1.7 Acetonitrile (CH3CN). Chromatographically pure.
3.2 reagent preparation
3.2.1 Waterborne, acidic, alcoholic, oil-based food simulants. Prepared in accordance with the provisions of GB 5009.156.
3.2.2 Sodium hydroxide solution (100g/L). Dissolve 10g of sodium hydroxide in 100mL of water.
3.2.3 sodium dihydrogen phosphate buffer solution (0.005mol/L, pH = 6.5). Weigh 0.780g sodium dihydrogen phosphate dihydrate, with 900mL water-soluble
Solution, adjust its pH to 6.5 with 100 g/L sodium hydroxide solution (3.2.2), and then make up to 1000 mL with water.
3.2.4 Isopropyl alcohol solution (100 mL/L). Measure 10 mL of isopropanol dissolved in 100 mL of water.
3.2.5 Methanol-Water Mixture (11). Measure 100 mL of methanol and add it to a volume of 100 mL of water.
3.3 Standards
3.3.1 Melamine (C3H6N6) (CAS number. 108-78-1). Purity ≥99%.
3.4 standard solution preparation
3.4.1 Melamine Standard Stock Solution (1000mg/L). Accurately weigh 50mg melamine standard, accurate to 0.1mg
In a 50 mL volumetric flask, add 40 mL of water and sonicate in a water bath (temperature of 70 °C) for 15 min to 30 min so that melamine can be fully used.
Dissolve, cool to room temperature, and then make up to volume with water. Store at a temperature of 4°C to 20°C in the dark. The concentration remains stable for 6 months.
3.4.2 Melamine standard intermediate solution (100mg/L). Pipette 5.00mL melamine standard stock solution into a 50mL volumetric flask.
Water volume.
3.4.3 Preparation of standard working solutions for food simulants
3.4.3.1 Standard working solution for water-based, acidic, alcoholic food simulants
Accurately absorb melamine standard intermediate solution (3.4.2) 0mL, 0.125mL, 0.250mL, 1.25mL, 2.50mL in 25mL
In the volumetric flask, the volume of melamine was 0 mg/L, 0.500 mg/L, and 1.00 mg/L, respectively.
5.00mg/L, 10.0mg/L. In the same way, the same concentration series of melamine was formulated with acidic and alcoholic food simulants, respectively
Standard working solution.
3.4.3.2 Standard working solution for oily food simulants
Accurately weigh 5g (accurate to 0.01g) of oily food simulant (refined corn oil or olive oil) into 5 25ml bottles
In a glass test tube, 0 μL, 25.0 μL, 50.0 μL, 250 μL, and 500 μL of melamine standard intermediate solution (3.4.2) were transferred using an adjustable pipette.
In the test tube, a standard working solution of an oily food simulant was obtained, in which the concentrations of melamine were 0 mg/kg and 0.500 mg/kg respectively.
1.00 mg/kg, 5.00 mg/kg, 10.00 mg/kg. Add 5.0 mL of isooctane (3.1.6) to each tube, and then add 5.0 mL
The isopropanol solution (3.2.4) was used to ultrasonically extract the test tube in a constant temperature water bath at 70° C. for 30 min and then centrifuged to separate layers. Suction of the lower aqueous solution
1mL~2mL, through a 0.22μm organic phase microporous membrane filtration solution obtained for high performance liquid chromatography injection measurement.
3.5 Materials
Organic phase microporous membrane. 0.22 μm.
4 Instruments and Equipment
4.1 High Performance Liquid Chromatography. Configure an ultraviolet absorption detector or a light emitting diode array detector.
4.2 Vortex oscillator.
4.3 ultrasonic thermostatic water bath.
4.4 Centrifuge. speed greater than 4000r/min.
4.5 Analytical balance. Sensitivity 0.0001g and 0.01g.
5 Analysis steps
5.1 Food simulant preparation
5.1.1 Preparation of food simulant soaking solution
According to the intended use and the conditions of use of melamine-formaldehyde resin and its molded products, it shall be in accordance with the requirements of GB 5009.156 and GB 31604.1.
Require, select the corresponding food simulants and migration test conditions to carry out the migration test, you can get the food simulant soaking solution. If the food model
Imitation soaking solution can not be tested immediately, the food simulant soaking solution should be stored in the refrigerator at 0°C~4°C from light.
After the temperature of the soaking solution of the food simulant is consistent with the room temperature, the next test solution is prepared.
5.1.2 Preparation of food simulant test solution
5.1.2.1 Water, Acid, Alcohol Food Simulator Test Solution
Accurately weigh approximately 1 mL of the aqueous, acidic, and alcoholic food simulant soak solution obtained after the migration test and pass 0.22 μm organic phase.
The filtrate obtained from the filtration of the microporous membrane was used for the determination of high performance liquid chromatography.
5.1.2.2 Oil Food Simulator Test Solution
Accurately weigh 5g (accurate to 0.01g) of the oily food simulant soaked in the migration test and place in a 25ml stoppered glass test tube
Add 5.0 mL of iso-octane, and then add 5.0 mL of isopropanol solution. Place the test tube in a constant temperature water bath at 70°C.
30min, then centrifugal stratification. Aspirate the lower aqueous solution 1mL~2mL, and pass the 0.22μm organic phase microporous membrane filter to obtain the test
Liquid for high performance liquid chromatography sample injection.
5.1.3 Preparation of blank test solution
Water-based, acidic, alcohol-based food simulants not in contact with food-contact materials or product samples should be handled in accordance with 5.1.2.1.
According to the operation of 5.1.2.2, the sample was filtered to obtain a blank test solution.
5.2 Instrument Reference Conditions
a) Columns. Amino columns, column length 250 mm, column diameter 4.6 mm, particle size 5 μm, or an equivalent column.
b) Mobile phase. acetonitrile-sodium dihydrogen phosphate buffer solution (75 25, volume ratio).
c) Flow rate. 1.0 mL/min.
d) Column temperature. room temperature.
e) Injection volume. 20 μL.
f) Detection wavelength. 230 nm.
g) Time. 20 minutes.
5.3 Making a standard working curve
According to the instrument reference conditions listed in 5.2, the standard working solution was tested and the corresponding peak area was determined. With melamine concentration as horizontal
Coordinates, with the corresponding peak area as the ordinate, are plotted against the standard working curve of the food simulant to obtain a linear equation.
5.4 Determination of food simulant test solution
According to the reference conditions of the instruments listed in 5.2, the food simulant test solution was tested, the retention time was qualitative, and the peak area was quantified.
The quasi-operating curve gives the concentration of melamine in the test liquid. At the same time, blank test solution was tested.
6 Expression of analysis results
6.1 Calculation of melamine concentration in food simulants
The concentration of melamine in the food simulant test solution was obtained from the standard curve, and the migration amount was calculated according to GB 5009.156 to obtain the food
Contact materials and products in melamine migration. The calculation results retain two significant figures.
7 Precision
The absolute difference between two independent determinations obtained under repeatability conditions must not be greater than the arithmetic mean of these two determinations
10%.
8 Others
The detection limit of this method for melamine in aqueous, acidic, and alcoholic food simulants is 0.2 mg/L, and the oily food simulants
The detection limit of melamine was 0.2 mg/kg.
This method limits the quantification of melamine in water-based, acidic, and alcohol-based food simulants to 0.5 mg/L, and the oil-bas......